Gregorio Igartúa de la Rosa (“Igartúa”) brings his federal constitutional appeal to us a third time, contending that his inability to vote .for the President and Vice-President of the United States of America on account of his residency in Puerto Rico is a redressable violation of his right to equal protection as a United States citizen. We affirm the district court’s dismissal of his claim, relying on our prior dispositions in Igartúa De La Rosa v. United States, 32 F.3d 8 (1st Cir.1994), cert. denied, 514 U.S. 1049, 115 S.Ct. 1426, 131 L.Ed.2d 308 (1995) (“Igartúa I”) and Igartúa De La Rosa v. United States, 229 F.3d 80 (1st Cir.2000) (“Igartúa II”). In Igartúa II, referring to Igartúa I, we noted that “this court held with undeniable clarity that the Constitution of the United States does not confer upon United States citizens residing in Puerto Rico a right to participate in the national election for President and Vice-President.” Igartúa II, 229 F.3d at 83.
Our prior opinions canvass the relevant constitutional landscape. Igartúa II, 229 F.3d at 83-84; Igartúa I, 32 F.3d at 9-11. We need only observe that Igartúa has raised no argument that would bring the *314matter outside the usual “rule that earlier decisions are binding.” Igartúa II, 229 F.3d at 84 (discussing the two exceptions to the rule). Under First Circuit precedent, a panel such as ourselves is bound in the present circumstances by a prior panel’s ruling. Only the en banc court, i.e. all the judges of the First Circuit sitting together, can alter a prior panel precedent. See Williams v. Ashland Eng’g Co., Inc., 45 F.3d 588, 592 (1st Cir.1995) (“An existing panel decision may be undermined by controlling authority, subsequently announced, such as an opinion of the Supreme Court, an en bane opinion of the circuit court, or a statutory overruling.”). And, of course, the Supreme Court of the United States may, by certiorari or subsequent precedent, overrule a circuit opinion. Id. Indeed, it seems apparent that a definitive constitutional ruling of the magnitude sought here can, in the final analysis, only emanate authoritatively from the Supreme Court itself.
Affirmed.
. Campbell, Senior Circuit Judge and Howard, Circuit Judge.